Bulldozer



\ July 2 5, 1939. Q s. ALUN n 2,157,166

BULLDOZER Filed July 26, 1957 2 Sheets-Sheet 1 v k u O 1 CAS N u g a W *i N N I v Q I g: E/ 's l m C+ '/l O l N m 7 q) Uil) Q (un n? I I, O j l m l Q w u. I o

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PS BY l 011% TQJMW ATTORNEY G. S. ALLlN July 25, 1939.

BULLDOZER Filed July 26, 1937 2 Sheets-Sheet 2 MNK/ INVENTOR GFoeaf .5. H2L/rv g BY 'RNEY Patented July 25, 1939 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to improvements in bulldozers, and it has reference more particularly to novel means, of a manually actuated kind, simple in design, relatively inexpensive in 5 construction, effective, quick acting and easily operated, for lifting the bulldozer blade to any of its different working levels.

It is the principal object of this invention to provide a manual means of the above character, utilizing as a part thereof hydraulic cylinders and a hand pump whereby a hydraulic pressure may be built up in the cylinders to actuate pistons in the cylinders to elevate the blade to a desired l5 height; the pump also being adapted to provide will move to a lower position.

Other objects of the invention reside in th manner in which the hydraulic cylinders are mounted and connected so that the strain and stresses of lifting the blade will be applied to the track frames as dierentiated from being applied to the tractor main frame.

Still furtheriobjects of the invention reside in the details of construction and combination of parts, and mode of operation, as will hereinafter be fully described.

In accomplishing these and other objects of the-invention, I have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein- Fig. l is a side view of a bulldozer embodying the present invention.

Fig. 2 is a partial plan view of the same.

Fig. 3 is a detail of a hydraulic cylinder, as connected to the track frame, and showing diagrammatically the hand pump as connected with the cylinders.

Fig. 4 is an enlarged vertical cross section of the pump, showing its valve connections.

Fig. 5 is a cross sectional view, on the line 5-5 in Fig. fl, showing the relief valve connections.

While the present invention may Well be applied to tractors of various kinds, and also may be used with bulldozer blades and mounting of dilerent designs, it has here been shown as applied to a tractor of the crawler track type and with a blade mounting frame that is pivoted t a dead axle. It is to be understood that this is for purpose of explanation only and not necessarily a limitation.

Referring more in detail to the drawings- In its present embodiment, the bulldozer utilizes a tractor of the crawler, or self laying for relief of pressure medium from the cylinders whereby the blade, by reason of its own weight,

track type. The tractor is designated in its entirety by reference numeral l, and it includes the usual main frame structure, or chassis 2, wherein is mounted an engine, designated at 3. At opposite sides of the main frame, or chassis 2, are the track mounting frames designated generally by reference character 4, and at the opposite ends of these frames the track mounting and driving wheels 5 and 6 are contained therein. The endless traction belts, or tracks, 1 are extended about 10 the wheels 5 and 6. Between these wheels, the upper runs of the endless track belts are supported by idler rollers 8 and the lower run is likewise guided and held in ground contact by idlers 9; the idlers 8 and 9 being supported from the track frames 4 as is the usual practice. The means for driving the tracks is not herein shown as it constitutes no part of the present invention. but may be through any suitable kind of connections with the engine 3.

The two track frames 4 are arranged symmetrically at opposite sides of the main frame of the tractor and near their rearward ends are pivoted for oscillating action upon the opposite ends of a dead axle l5 which extends transversely through and is xed in the main frame of the tractor as a support for the latter. The forward end of the tractor would best be supported from the track frames 4 through the mediacy of springs, or other suitable means, not shown, to permit a relative upward and downward movement of the tracks incident to travel over uneven surfaces.

The bulldozer structure comprises also the usual transverse blade I8, located forwardly of the tractor and supported through the mediacy of a frame comprising two thrust beams --20 extending along the opposite sides of the tractor and operatively connected at their forward ends to the blade structure. At their rearward ends, these beams have brackets 23 fixed thereto and these, in turn, are formed with bearings whereby the brackets are rotatably tted to the opposite end portions of the dead axle i 5 at the outside of the tracks. Nuts 24 on the ends of the dead axle hold the parts properly assembled.

The means for supporting the forward ends of the beams 2li-20, to hold the blade in working position, or to lift it clear of the ground, comprises, at each side of the tractor, a hydraulic cylinder 3U. These cylinders have fixed mountings in trusses rigidly mounted on the beams adjacent their rearward ends. Each of these trusses comprises an upright, rear leg member 3l, that has its lower end solidly xed to its beam 20, 55

' with its upper portion, which leans slightly rearwardly, solidly ilxed to a channel beam Il, which extends forwardly and downwardly and is xed solidly to the beam at some distance forwardly of the upright leg; thus the beams 20, 3l and Il at each side. form a triangular truss in a vertical plane parallel with the tractor and upon the beam 2l.

l'he hydraulic cylinders 30 are of rather small diameter but are relatively long and are contained in or disposed alongside of the beams Il and have their upper ends fixed by bolts 3l to their respective trusses at the junction of legs 3| and beams 3l.

' Each cylinder Ill is fitted with a piston Il and this has a piston rod 4| )extending from the lower of thepistons and cables will cause the beams 2li-2li kto be lifted, thereby to lift the blade accordingly.

'I'he manual means which I-have provided for controlling the movement of the pistons in the hydraulic cylinders comprises a hydraulic hand pump 50 operated by a vertical handle or lever 5i As shown diagrammatically in Fig. 4, the pump comprises two pump cylinders M and l5, each `with a pump piston Il. The pistons are connected by links 58 with the lever UI. Alsothe two cylinders have pipe connections ll and $0 with a supply reservoir il; each pipe having a back check valve 62. Also, each pump cylinderhas an outlet pipe N with back check valve 'I'he aromas pipes 6I are connected with a cross pipe 6l which, at its opposite ends, respectively, connects with the lower ends of the hydraulic cylinders -30.

There is also a return pipe 'l0 leading back to the reservoir from the pipe 64 and containing a normally closed valve 15 that is adapted to be opened by a sidewise movement of the handle 5I be manually lifted, easily and quickly, to any desired height within its limits of travel.

Having thus described my invention, what I claim as new therein and desire to secure by Letters Patent is:

In a bulldozer, a tractor including track frames at opposite sides of a main frame, a blade mounting frame pivotally supported at its rearward end from the tractor and extending forwardly thereof for vertical oscillation at its forward end, a blade mounted by said frame, a truss mounted on the blade mounting frame near the pivoted end and comprising an upright member and a downwardly and forwardly inclined strut, a 'hydraulic cylinder mounted within the strut lengthwise thereof, a sheave wheel tlxed on the blade mounting frame at the lower end of the strut, a bracket ilxed, on the track frame and overhanging the said sheave wheel, a piston in the said cylinder, a'cable attached to the bracket and extending beneath the When this rod is def sheave wheel and having ilxed connection with GEORGE s. ALLIN. 

